If Facebook wanted to move to a hosting provider then what options do they have?

If Facebook wanted to move to a hosting provider then what options do they have?
They are big, lots of stuff to host and need more server resources. They have awesome datacenters but still just curious where will the host?

If they ever make such an attempt then it will be the end of Facebook as there is no hosting providers capable of hosting such a site smoothly.
They could consider Amazon AWS or Google Cloud if they wanna move.